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Geography Lecture 4 (5. Factors influencing climatic zones (Air mass…

- - - - Tropics have the highest amount of energy (energy surplus) among all latitudes. This is due to factors such as pathway of insolation and position of overhead Sun.
  - - - These winds are drawn to the ITCZ so they will bring seasonal rainfall to different areas in the tropics
        
        The monsoon in Asia can be attributed to the thermal variation in thermal capacities of oceans and land masses
        
        Winds can also induce maritime effect on coastal regions
    - - Surface winds spiral from STHP cells, feeding trade winds and mid-latitudinal westerlies
        
        On the eastern side, air subsides strongly, producing dry winds
        
        On the western side, air does not subside as strongly and thus brings warm, dry air to the continents
  - - - Hadley cell carries warm moist air to the equator. This causes the STHP to have little moisture
        
        ITCZ moves with the overhead Sun, thus causes rainfall to be seasonal in the tropics and the seasonality gets more extreme as latitude increases
    - - Small weather disturbances can become rotating wind systems (tropical depressions), and they are formed due to intense convection and condensation
        
        These can form cumulonimbus clouds which bring rainfall. These depressions may grow into cyclones
        
        They are free to move in the Hadley cell and can move over oceans to bring rain to land masses in the region
  - - - Inland and coastal regions have vastly different climates due to the temperatures of the regions
        
        The temperature differences are due to the Maritime and Continental effect
        
        Tropical monsoons can be attributed to the variation in the thermal capacities of continents and oceans
  - - - Ocean currents can cause heating or cooling to a specific region
        
        Surface Currents such as the Gulf Stream can cause warming of regions
  - - - Mountainous areas might change the local rainfall and temperature patterns
        
        Mountains inhibit rainfall on leeward side and cause orographic rain on the wayward side
- - - - Related to distance from the equator and amount of insolation
      - Related to relative position of the overhead Sun at noon
    - - ITCZ and its area of uplift, cloud formation and precipitation
      - STHP and its related descending air currents and clear skies
    - - Location of tropical, subtropical and polar air masses
      - Polar front and its area of cloud development and precipitation
      - Polar Vortex and its associated descending air currents and clear skies
    - - ITCZ, STHP, Polar Front and the position of air masses all move in response to the seasonal movements of the Sun
      - The type of climate that a location experiences is largely due to a migration of these weather features
  - - - The specific heat capacity of land and sea leads to changes in a region's temperature and pressure characteristics
      - For example, coastal lowlands such as Sydney, Australia and large continental masses such as Verkhoyansk, Russia
    - - Warm or cold ocean currents can affect temperature and precipitation of a region. Cold currents cool and inhibit rain, while warm currents do the opposite
      - Gulf Stream (warm) and Labrador Current (cool)
  - - - Mountain ranges can cause orographic rainfall (convection rain) by forcing moisture laden winds up the wayward side. The air cools and precipitation falls. On the leeward side, the air is dry and sinks
    - - The relationship between height above sea-level and corresponding decrease in temperature
- - - - Climates are close to desert conditions (arid, high variation in precipitation, high summer temperature, large annual and daily temperature ranges
        
        About 3-4 months of rainfall and seasonal temperature
        
        Vegetation consists of herbaceous plants, with short bushes and shrubs. These plants usually die every year and are called annual plants
    - - Generally in the western parts of continents
        
        Forms largely due to STHP and Hadley circulation
        
        Precipitation usually comes as localized showers from summertime convectional activity (less than 3 months of rainfall)
        
        Summer daytime temperatures can be extremely high (up to 50 degrees)
        
        This is due to clear skies allowing large amount of insolation, as well as low evaporation to remove heat
        
        This leads to large diurnal temperature ranges
        
        There is no vegetation
  - - - Monsoon climates are between Tropical wet and Tropical dry climates
        
        Rainfall is enhanced by orographic uplift
        
        East coasts of land masses experience the trade wind effect with the winds blowing from east to west (produced by maritime tropical(mT) and maritime equatorial(mE) winds)
        
        Mid-latitude cyclones may form and cause excessive precipitation
        
        High fluctuating rainfall and high temperatures
        
        Monthly mean temperatures are similar to Af
        
        Vegetation is usually lush but not as dense as Af
    - - Most of these exist within 10 degrees
        
        They have no dry period as they are constantly under the influence of ITCZ
        
        Their precipitation is usually convectional with strong solar heating, triggering brief and heavy thunderstorms in the mid to late afternoon
        
        Temperatures are usually high
        
        Formation of cumulus clouds scatter insolation
        
        High humidity and cloud cover retard nighttime cooling
        
        Vegetation include rainforests with dense canopies and large species diversity
    - - Tropical Savannah climates are nearest to the poles among tropics, and owe their climate largely to the Hadley cell
        
        6 months of rain, 6 months of no rain, but generally lower than Af and Am
        
        When ITCZ coincides, rain forms
        
        Generally low temperature range (3-10)
        
        Diurnal temperature is considerably large (15-30)
        
        Vegetation consists of mainly grasses and widely scattered trees